FILE - In this Oct. 8, 2016, file photo, Ohio State quarterback J.T. Barrett plays against Indiana during an NCAA college football game in Columbus, Ohio. Barrett is the Big Ten’s best chance for the Heisman Trophy. His downfield passing can be hit-or-miss, but he’s a playmaker and he wins. (AP Photo/Jay LaPrete, File)

FILE - In this Oct. 8, 2016, file photo, Ohio State quarterback J.T. Barrett plays against Indiana during an NCAA college football game in Columbus, Ohio. Barrett is the Big Ten’s best chance for the Heisman

Ohio State and Michigan at the top of the Big Ten East is no surprise at the halfway point of the season, but who would have imagined defending conference champion and 2015 College Football Playoff participant Michigan State having only two wins?

Nebraska leads the West, though its schedule gets significantly tougher after this week, and defending division champ Iowa is a half-game behind and regaining its traction after losing at home to North Dakota State and Northwestern.

Here's an overview of what's happened so far in the Big Ten:

BIGGEST SURPRISE

Indiana is only 3-3, but the Hoosiers are much improved . They've started to play good defense, finally, and that's largely because of Kevin Wilson hiring of coordinator Tom Allen. Allen's aggressive 4-2-5 defense allowed Indiana to beat Michigan State, play Ohio State close into the fourth quarter and give Nebraska a scare. The Hoosiers are kicking themselves for losing to Wake Forest at home, but they likely to make a bowl for the second straight year.

BIGGEST BUST

Michigan State is a mess. The Spartans can't decide on a quarterback, rank last in the Big Ten in rushing, miss tackles at an alarming rate and don't seem to have their signature toughness. Last week Northwestern scored 54 points , the most points allowed by an MSU team since 2003. The Spartans must win four of their last six just to be eligible for a bowl, and they still have to play Michigan and Ohio State.

BEST TURNAROUND

Nebraska is 6-0, ranked in the top 10 for the first time since 2011 and alone in first place in the West. A year ago at this time the Cornhuskers were 2-4 and on their way to a 6-7 season. The close losses in 2015 are close wins this year , and they're playing with the confidence that comes with having a greater understanding and comfort in the offensive and defensive systems under second-year coach Mike Riley.

BEST IN-SEASON TURNAROUND

Northwestern, which won 10 games last year and had high hopes, was 0-2 after losing at home to FCS Illinois State. The Wildcats have cranked up their offense the last couple games, and they're only a game behind Nebraska in the West.

TOP ALL-AROUND PLAYER

Michigan's electrifying Jabrill Peppers , listed on the roster as a linebacker, has lined up all over the field. Peppers ranks among the national leaders in tackles for loss, he covers and returns kicks and is the country's No. 2 punt returner. He also has played some offense, taking snaps out of the wildcat formation.

TOP OFFENSIVE PLAYER

Ohio State quarterback J.T. Barrett is the Big Ten's best chance for the Heisman Trophy. His downfield passing can be hit or miss, but he's a playmaker and he wins. That was never more apparent than last week at Wisconsin.

TOP DEFENSIVE PLAYER NOT NAMED PEPPERS

Wisconsin linebacker T.J. Watt has overcome injuries the last two years to become one of the conference's most disruptive forces. J.J. Watt's little brother, and a converted tight end, he leads the Badgers with 5.5 sacks and eight tackles for loss.

BIGGEST MIRAGE

DJ Durkin's first season at Maryland started 4-0 with points piling up at a fast clip. The Terrapins have scored a total of 24 in losing their last two games, their QB situation is in flux and the turnover bug has cropped up again. They probably will be favored in only one of their final six games (at home against Rutgers).

WORST LUCK

Penn State has had seven linebackers injured so far, including starters Jason Cabinda, Brandon Bell and Nyeem Wartman-White. Not even "Linebacker U." can withstand so many casualties. The good news is that the Nittany Lions are getting healthier, and just in time with Ohio State visiting this week.

BEST GAME (so far)

Ohio State's 30-23 win at Wisconsin. Barrett had 199 of his 318 total yards and all three of his touchdowns after halftime, including the game-winner to Noah Brown in overtime, in a matchup of top-10 teams that lived up to its billing.

WORST GAME (so far)

Michigan's 78-0 win at Rutgers. The Wolverines did whatever they wanted. The Scarlet Knights were limited to 22 yards total yards and two first downs.

COACHING CAROUSEL

Purdue fired Darrell Hazell on Sunday to get a jump on the coaching search. The Boilermakers showed glimmers of hope early in the season, but Hazell couldn't survive 49-35 homecoming loss that really wasn't that close.

Minnesota's Tracy Claeys is in his first full season as Jerry Kill's successor and in the first year of a three-year contract. The Gophers are 4-2, but after losing an ugly game to Iowa he could really use a win over Nebraska or Wisconsin to fend off skeptical fans.

Lovie Smith is off to a 2-4 start at Illinois, has QB issues and undoubtedly still wringing his hands over losing at home to Purdue.

Chris Ash knew Rutgers would be a tough job — the Knights went 11 quarters without scoring — but he surely couldn't have imagined it being like this.